1. Field of Application
This invention relates to file cabinets; and more particularly to positive interlocks for lateral filing cabinets.
2. Description of the Prior Art
Filing cabinets, of the type that are commonly found in offices, businesses and homes, for filing documents, papers and the like are generally of the vertical and lateral type. Such filing or file cabinets usually include a number of file drawers each of which, by way of example and explanation, has a width, a height and a length. In a vertical file the length of the drawer is moved out from the body of the file cabinet to obtain access to the drawer space; while in a lateral file the drawer is moved transverse to its length to obtain access to the drawer space.
One prevalent problem with lateral type filing cabinets is that there is a tendency of the cabinet to tip over if more than one drawer is moved to open position at a time. This seems to be due to a shift in the center of gravity such that the cabinet becomes unstable in the forward (drawer opened) direction. Obviously, a falling filing cabinet can be a dangerous object which can, and sometimes does, injur the party in front of the cabinet. In addition, if the cabinet falls over, the drawers and cabinet may be damaged and stored materials upset and damaged also.
One available method of preventing lateral files from tipping over is to attach the cabinet to a wall or other support if possible. This usually requires modification to the cabinet and restricts positioning of the filing cabinet where there is a wall or support the cabinet can be attached to.
Alternatively, mechanisms have been devised for mechanically interlocking the cabinet drawers in such a manner that withdrawal of one drawer hinders or prevents withdrawal of all other cabinet drawers. One type of such available interlock mechanism is shown in Canadian Letters Pat. No. 1,038,010 issued Sept. 5, 1978 to C. C. Pergler for Safety and Drawer Movement Sequencing Control Arrangement For File Cabinets. However, Pergler requires a dual bar system; one of which consists of a stack of latch bars actuated by a cam of a moving drawer, and the other of which acts in response to movement of the first latch bar to latch all closed drawers shut until the opened drawer is returned to closed position. Not only is the Pergler type mechanism relatively highly complex, and thus relatively expensive, but it will also not prevent simultaneous opening of two cabinet drawers.
Another available type of interlock mechanism is shown in Canadian Letters Pat. No. 1,133,564 issued on Oct. 12, 1982 to L. Terlecki for Lateral File And Interlock. This type of interlock mechanism provide an interlock latch bar for each cabinet drawer, with the latch bars arranged in a vertical stack or array so that they can coact with each other as well as with their respective cabinet drawers. The stack of latch bars are sized and arranged in the cabinet to take up all the vertical space therein; except for a space the size of an interlock channel, one of which is attached to each cabinet drawer side. In this type of interlock mechanism when a cabinet drawer is moved to open position the channel is moved between a corresponding set of latch bars to fill the single available space and lift up all latch bars thereabove in the cabinet. Resistance to any attempt to thereafter open a second drawer, above the opened drawer, is provied by the top of the cabinet which prevents further upward movement of the latch bar stack. Continued force to so open a second drawer could thus damage either the cabinet top or one or more of the latch bars. In addition, such mechanisms require the expense of providing a latch bar for each cabinet drawer.
Other available types of interlock mechanisms are shown in Canadian Letters Patent No. 1,037,092 issued on Aug. 22, 1978 to G. Brekner et all for Office Appliance; Canadian Letters Patent No. 1,037,093 issued on Aug. 22, 1978; and Canadian Letters Patent No. 1,114,883 issued on Dec. 22, 1981. All such mechanisms not only also require a stack of latch bars including a latch bar for each drawer; but also actuate the latch bars by way of cams which must be first moved to a latch bar actuating condition and thereafter returned to an unactuated condition. Thus again, there is an undesirable expense and relative complexity of a latch bar for each drawer; as well as the undesirable relative expense of the cams and their operation.
Still other available types of interlock mechanisms connect an interlock track to the side of each cabinet drawer; but, must do so, so that the track is slotted to provided for relative movement between the track and drawer. This action is necessary to accommodate the overall length of the cabinet and the required travel to allow a drawer to be fully opened. However, the resulting undesirable effect is that all drawers can be opened a relatively small amount but one which may be enough to shift the cabinet's center of gravity and cause tipping of the cabinet.